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How to prevent galling on stainless steel bolts & nuts
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I produce pipe couplings and stainless steel clamps.The bolts which tighten the products as the nuts are made of stainless steel 304.I have problems of galling (cold welding).I would like to know what kind of lubricant can use (need to be dry ..or dirt will stick to it while installing the product ).I also need the machine or the process to coat it .
Danny Krausz
- Tel Aviv, Israel
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To prevent galling on type 304 stainless steel we suggest hard chrome plating a deposit of .0003"-.0005" thick.
Stephen C. Ward- Canada
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We use to apply a Teflon coating on the bolts and nuts to prevent galling. It works very well.
Jordi Pujol- Barcelona
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I am considering using 304 Stainless steel bolts to connect aluminum (6061) shape to aluminum (6061) plate. In this application I need to minimize the amount of magnetic material inside my vessel and I cannot use a lubricant because the vessel is under a vacuum. I am concerned about galling. Do I have to chrome plate the fasteners? Is this very expensive? Any other options?
Donald Sokol- Oak Ridge, TN
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Two approaches I have heard of is silver plating the bolts or using Nitronic stainless steel, a grade designed to prevent galling.
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
August 12, 2009
In addition to above methods kindly let me know if Xylan coating of SDSS fasteners also prevent galling
Ravindra Maurya- Mumbai, India
August 12, 2009
Hi, Ravindra. Anything that prevents the stainless from contacting the stainless will prevent galling. But for good answers, please try to follow the style of the two previous inquiriers and describe your own situation instead of casting the proposition in the abstract. Thanks.
Regards,
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 Ted Mooney, P.E. finishing.com Brick, New Jersey |
September 24, 2010
I have run into galling problem with stainless steel nut on stainless steel threaded part. Would it work better if I use cadmium plated nut on stainless steel threaded part?
Kenneth Laiproduct designer - Woburn, Massachusetts, USA
September 27, 2010
Hi, Kenneth.
Cadmium is a biocumulative poison very similar in its effects to mercury and lead, and we are all working hard to get it out of the environment except when it is especially necessary. A key to whether it is necessary is whether there is a combination of properties required which substitutes cannot meet. When you are looking to match only a single property (non-galling), cadmium is probably the wrong choice. Good luck.
Regards,
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Ted Mooney, P.E. finishing.com Brick, New Jersey |